Many modern and known satellite ADCS are based on “star tracker” or telescope-based technology, which may be coupled with reaction wheel or control gyroscope subsystems for attitude control. Such conventional star tracker systems and subsystems thus incorporate a telescope mounted to a satellite, with the telescope being configured to take images of stars viewable thereby in orbit. In this manner, the images captured by the telescope enable determination of the orientation of the telescope and thus the satellite to which it is mounted.
Upon determination of attitude, attitude control is necessary to properly steer, redirect, repoint, or otherwise move satellites and the systems and/or telescopes mounted thereto. Challenges exist with the ability to slew quickly, but also under control. Thus, at one time, slewing with the satellite turned on was simply avoided. Instead, the satellite would simply be turned off during reorientation to a new direction. It could then be turned back on, the viewable stars scanned and compared to star tracker based and stored images, based upon which it could be determined whether the satellite is or is not positioned in the desired direction. As would be expected, such approaches were time-intensive and generally duplicative as validation would more often than not determine that the satellite needs further repositioning due to errors or otherwise.
In more recent years alternative systems and methods of attitude control have been implemented, whereby, for example, if movement is maintained at a sufficiently slow rate the star tracker may be kept on during movement. Recalculation of position may occur repeatedly, providing the star tracker can focus upon and identify a single star for extrapolation. Thus, knowledge of orientation may be maintained throughout slewing, thus reducing at least certain of the inaccuracies and inefficiencies with systems such as the “on/off” one described above. Challenges, however, remain as slewing speed had to be sacrificed to maintain accuracy of determinations during slewing. Still further, such techniques were oftentimes cumbersome and/or unworkable with smaller sized satellites. Thus, a need exists for a consolidated, accurate, and efficient system and method for attitude determination and attitude control during satellite slewing operations.